An effort to root out political "extremism" in the military despite little evidence of any such extremists actually operating within the ranks. It means anyone who disagrees with them or their thinking.
A TYPICAL COMMUNIST MOVE TO ELIMINATE PEOPLE THAT DISAGREE WITH YOU.

A manufactured panic over the January 6 rally has provided Biden and his flunkies with an excuse to attack the U.S. military. The Biden administration has implemented an effort to root out political "extremism" in the military in order to work toward a military with more 'diversity, equity, and inclusion', despite little evidence of any such extremists actually operating within the ranks: